جستجوی مقالات مرتبط با کلیدواژه « Traffic » در نشریات گروه « جنگلداری »

In this study, the accumulation of heavy metals included lead and nickel in Albizia lebbeck ((L.) Benth) tree, and Conocarpus erectus (L.) shrubin urban green spacewere investigated. To this, two areas with low and high traffic intensity with three replications were selected in Ahwaz, and random samples were collected from tree leaves (from 2 to 3 meters height above the ground level) and soil at the bottom of the species (depth 0 to 10 cm). The results showed that in the low traffic area, the concentrations of both heavy metals in two species were significantly different, in the case of lead, the concentration of this metal in the leaf of C. erectus was significantly higher than that of A. lebbeck, but the concentration of nickel in the leaf of A. lebbeck was significantly higher than that of C. erectus. Concentrations of lead and nickel in the soil of both species in the high traffic areas were significantly higher than the low traffic areas. The bioconcentration factor for the lead metal in both species was less than 1; But, for nickel metal, the mean of bioconcentration factor for both species is greater than 1; indicating that the two species are able to extract nickel from the soil. In summary, it can be stated that according to the findings of this study, C. erectus is more capable of absorbing nickel than Albizia lebbeck and can be used in phytoremediation projects in similar areas.

Using modern machinery for logging will entail considerable pressure to the soil and cause serious damage to the soil and reduce the carbon sequestration. Many studies show the long-term recovery of soil physical and chemical properties. The aim of this study was to investigate the effects of skidding slope, traffic, and place of the wheel on the carbon stocks and estimate the economic value of these reserves to obtain the information needed for comprehensive decision-making about the management of forest resources. The treatments included two slope classes (>10% and ≤10%), each class includes three traffic levels (low, medium and high), and in each group, on the wheels route, middle route, and control area, four samples were taken in three replicates. The economic valuation of the carbon sequestration function was determined using the shadow value method. The results showed that with increasing the slope path, the number of traffic and on the wheel route, the amount of carbon sequestration decreased significantly. The value of each hectare of the study area in terms of soil carbon sequestration and organic layer up to a depth of 10 cm was estimated about 1798.8 $ per hectare. On the other hand, reducing carbon sequestration in skid trails costs an average of 5,166 $ per hectare annually. Awareness of these costs will help the policymakers in the conservation and allocation of financial resources, especially in the context of budget constraints.

Ground skidding damages the marginal trees of the skid trails and may decrease their growth increment at long period. In this research the effects of ground skidding on decay development and extent of the beech trees (Fagus orientalis Lipsky) adjacent to the skid trails, at four age classes, including: 0-5, 5-10, 10-15 and 15-20 year were investigated. After classifying the skid trails to three traffic levels, including: low, moderate and sever, depending on their distance to depot location and trails intersections, the time required for wave transit across the marginal trees at three directions, consisting of: wound direction, wound cross and stem longitudinal direction, was measured, using a stress wave velocity apparatus. After data correction by the apparatus correction coefficient, the tree’s stress wave velocity at the three directions were calculated then statistically analyzed. The results showed that more than 75% of the trees located at 1.5 m. distance adjacent to the skid trails, were wounded by the skidders which resulted in 25% decay. There was also not any decay in the unwounded trees adjacent to the skid trails. Therefore the decay extended when the age of the skid trails increased. Most of the decays were found at trees located at the skid’s trails curves and t down slopes. The results of this research demonstrate an irretrievable, but preventable damage to the standing trees within the skid’s activity extent.